Questions tagged [experimental-technique]
filling in the unspecified details of elegant-sounding descriptions of experimental methods.
289
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How is a spectrometer is calibrated for intensity?
For the case of spectrophotometers, we can easily calibrate the device(intensity wise) taking the light source inside the device as the reference, without any need of precise knowledge about its ...
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2answers
35 views
Linear Regressions vs Algebra & Averaging in Solving for a Constant
I'm current taking AP Physics, and in both of the labs performed so far (Snell's Law/Refraction and Galileo's Inclined Plane), I have been trying to calculate some constant from a linear relationship ...
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1answer
19 views
Would SiPMs respond differently to scintillation light from neutrons vs. gammas?
I have a fast-neutron scintillator which also is sensitive to gammas (much less so, though). When I connect it to a SiPM instead of a PMT, the gamma pulses (obtained from performing pulse shape ...
0
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1answer
29 views
Why photodiode measures random phase superpositions on continuous-wave (10kHz) white light?
I measured a 10 kHz modulated white light using a photodiode (Thorlabs PDA10A):
Unexpectedly, the photodiode output sensitively depends on the orientation and position of the photodiode. For two ...
3
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3answers
127 views
Does frequency of light change in the LIGO interferometer arms?
There are a number of questions on the internet and on this site asking about how the LIGO interferometer measurement works given that the gravitation wave stretches both the length of the ...
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0answers
78 views
Initial conditions in QM
My questions are about initial conditions in QM in experiment and in lab.
We consider many different initial wave functions, and we solve the problem on paper. Now, I have 2 questions about this in ...
1
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1answer
37 views
Do we need to know Earth's magnetic field locally?
I'm a high school student and in our course we have elements of earth's magnetic field (dip and other stuff) that lets us know the value and direction of magnetic field at any point on the planet.
I ...
1
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1answer
108 views
Experiment: Magnet falling in a copper/aluminum pipe
We know that when we release a magnet in conducting pipe (aluminum, copper, etc..) it will be subjected to a magnetic force induced by the induced current. This magnetic field will be created in a ...
2
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0answers
29 views
How to identify properties of a concave diffraction grating
As a little side project I want to build a spectrometer. The main components are an entrance slit, a concave diffraction grating and a CCD sensor (also the electronics). I bought a used diffraction ...
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3answers
67 views
$CO_2$ heating experiment (high school)
A student is trying to run some experiments for a project to explore how the concentration of CO2 affects the temperature of air. For this, she:
Drops different ammounts of dry ice (between 0 and 2....
1
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2answers
89 views
How Do Scientists Measure Subatomic Particles? [closed]
I'm asking for a list of experiments, machinery, technology and techniques. The only measuring device I really know of is the Stern-Gerlach contraption. Google hasn't been helpful (it only gives me ...
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0answers
115 views
How do measurements of $G$ account for variations in the local gravitational field?
One of the notable discrepancies of modern physics is the current disagreement of measurements of the gravitational constant $G$, well beyond reported uncertainties (and agreeing only to about 1 part ...
0
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1answer
161 views
How to determine the focal length of a combination of two convex lenses separated by a distance $d$ experimentally without formula?
I have done this experiment to find out the equivalent focal length of a combination of 2 convex lenses of slightly different focal length and have applied the formula for the equivalent focal length ...
0
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0answers
29 views
Experimental preparation of quantum states of macroscopic systems
What will be the experimental procedure to put
the center of mass degree of freedom of a macroscopic object in a quantum superposition of widely separated states?
I have been reading some papers ...
0
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1answer
66 views
Monte Carlo Closure Test in Particle Physics
What is the principle behind a MC Closure Test employed while analysing data in particle physics?
So, what I understand here is that this test checks if one's code is working properly or not ...
0
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0answers
24 views
Why doesn't a lock-in measure the full voltage from a function generator? (3$omega$ setup)
I'm trying to build a setup for the 3$\omega$ technique, and the equipment is making my brain hurt.
When I send a signal directly from the function generator to the lock-in, it only measures about 71% ...
0
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0answers
14 views
Skin Effect in two cilindrical conductors in contact
I have to prepare an experiment for my lab class and I'm planning on measuring the resistivity of an aluminum cilinder at different temperatures by putting it inside a coil with an alternating current....
0
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0answers
25 views
is there any experimental method for measurement of thickness at atomic scale?
is there any experimental method for measurement of thickness at atomic scale?
there are some methods for measurement of thickness even at nano scales such as AFM,TEM but my question is about atomic ...
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2answers
80 views
Experimental setup for 1 dimensional constrained frictionless motion
Physics textbooks are full of examples considering one dimensional constrained motion (in the gravitational field) with neglectible friction.
However I have never seen setups with curved paths where ...
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0answers
54 views
Photo Multiplier Tube (PMT) and charge sensitive pre-amplifier
I have an H7195 assembly type Photo Multiplier Tube (PMT) used to be tested for single photon measurement. I would like to use the dynode output to check the spectrum by connecting to a charge ...
2
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0answers
49 views
How Is Are Parton Distribution Functions (PDFs) Determined In Practice And In Theory?
I have put my actual questions in bold normal font, and the rest of this question clarifies what I mean to be asking, especially in terms of the depth and kinds of information I am looking for. ...
2
votes
1answer
72 views
Simple heater (radiation) model for PID constants tuning
I've searched around a lot and maybe I just don't know what exactly to search (and even ask here) for, but I'd like to create a simple model/function of a heater dissipating heat to surrounding air, ...
1
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1answer
41 views
What does it mean to hear the gravitational waves?
In last few years, I watched a lot of YouTube videos claiming that gravitational waves can be and has been heard. They also play a short audio signal. How do experiments such as LIGO replicate the ...
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0answers
21 views
How to change the diameter of a water stream?
So I am conducting experiments investigating the change of sound as a bucket fills up with water. One of the parameters which changes the sound heard is the diameter of the stream of water filling up ...
1
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2answers
104 views
Does Michelson-Morley experiment really disprove the existence of aether?
In the MM experiment, the speed of one light beam was supposed to slow down as it moved against the flow of aether, but when it bounced off the mirror, it would be moving in the opposite direction--...
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0answers
25 views
Generic modes of light
Typically in second quantization one employs creation and destruction operators for modes which are eigenstates of the momentum: $a_{k}, a^{\dagger}_{k}$ where $k$ is the momentum eigenvalue. The "...
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0answers
28 views
What are the dynamics of a rope wrapping around a pole of given radius?
Suppose we drop a mass m from an initial angle $\theta_o$ connected to the pole of radius r with a rope of initial length $l_o$. As the system is released, the rope wraps around the pole, decreasing ...
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2answers
29 views
Do you have an idea for two easy experiments to measure the coefficients of static and sliding friction of a rope wrapped around a steel rod?
I'm researching a phenomenon dependent on the Capstan/Euler-Eytelwein-Equation. To model a simulation, I need the friction coefficients. I came up with the idea of hanging one mass $m_1$ on one side ...
1
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1answer
63 views
What is the scientific method for finding a theoretical explanation for experimental data?
Say you observe some effect that you did not anticipate in one of your experiments. You have checked the experimental setup and you're sure it's not just a systemic error but an actual measurement of ...
1
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1answer
35 views
spot welding technique
I am trying to make electrical contacts by the spot welding technique. For Hall effect measurements, the contact size should be as small as possible and the sample is very very thin(0.025mm). But ...
2
votes
1answer
78 views
Experimental considerations for measuring the gravitational constant/effects, with two large (1000kg) masses orbiting each other? [closed]
So @uhoh, wanting to get some experimental data to verify Limits on non-Newtonian gravity at length scales larger than 1 meter?, proposed an experiment:
Place two large (1000kg) spherical masses in ...
2
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0answers
57 views
How did Henry Kater measure distances down one part in $10^5$?
Wikipedia says that in 1817, Henry Kater was able to measure distances accurately enough to get at least five significant figures in a measurement of $g,$ suggesting that he could measure a distances ...
24
votes
3answers
1k views
How to fix a bad KF flange?
Here is an interesting question for those who are familiar with vacuum science techniques. In the attached picture we have a damaged surface of a KF flange, which comes from the turbo pump outlet and ...
3
votes
2answers
258 views
Torricelli's law doesn't seem to apply in an experiment. Why could this be? What is going on?
For physics class we've done this experiment where we would measure the speed of the water escaping from a water bottle through a hole in a side of it. We would calculate the speed through kinematics ...
0
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1answer
92 views
How can one experimentally measure the velocity of water flowing through a pipe?
I am planning to investigate the effect of bend curvature of a pipe on velocity of water. For this, I will need to find the velocity of water through various pipe bends. Would placing an object in the ...
0
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0answers
25 views
Porous nanostructure in TGA and DSC
How does the porosity in porous nanostructures, such as mesoporous silica, influence the observed response in Thermal Gravimetry Analysis (TGA) vs Differential scanning calorimetry (DSC) thermograms?
2
votes
1answer
230 views
What is the most efficient way to pour a liquid through a funnel?
Be it in cooking or an experiment, when transferring liquid from one container to another using a funnel should you:
(a) pour it all straight into the funnel, filling it up and waiting for the liquid ...
0
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1answer
227 views
Strain gauge vs linear variable displacement transducer
For measuring deformation experiments, it seems that strain gauges and linear variable displacement transducers (LVDT) are commonly used. If the material exhibits geometric linearity, then couldn't we ...
0
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1answer
71 views
Measure temperature of a heater wire
I would like to measure the temperature of a heating wire (tungsten) that's wrapped around my sample.
Does anyone have a better idea than using a infrared thermometer, which has relatively low ...
1
vote
2answers
81 views
Why are gradient and graphs used in labs? [closed]
This may seem like a redundant question but I was wondering why gradient calculations are preferred when calculating a value by experiment as opposed to just plugging in raw values me getting an ...
1
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1answer
75 views
The uncertainty of a toy car's measured average speed
Suppose I have a battery-powered toy car, and I am told to design an experiment which would allow me to determine the average speed of that toy car over, say, a meter, and to account for experimental ...
2
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1answer
70 views
Turning off an inductor: Experimental problems
I am trying to measure the current in dependence of time in turning on and off an inductor.
If I choose an inductor with low inductivity (36 mH) it works for turning on (almost) as expected, but for ...
3
votes
1answer
78 views
How does one actually 'fire an electron'?
As a mathematician, I have practically zero experience and knowledge of experimental methods. Recently, learning about some famous experiments in the history of quantum physics, I heard about an ...
0
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1answer
101 views
Significant figures in a practical experimental problem [duplicate]
Here is a question that combines uncertainties in measurements and significant figures.
Consider the following results to measure the value of g:
$$g={9.7,9.8,9.7,10.0,10.1,10.3}$$
Then to four ...
0
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1answer
39 views
Noise reduction approaches in optical spectral measurement
I am using an optical spectrometer to measure some surfaces in the visible, and since the signal is quite noisy I wondering what would be the best way to reduce the noise.
In particular, are there ...
-1
votes
2answers
577 views
Methods to convert nitrogen nuclei to oxygen nuclei?
Are there any "safe" method that allows converting the nitrogen into oxygen?
There's Ernest Rutherford that uses alpha particles aimed at the nitrogen to create oxygen and hydrogen.
But are there ...
0
votes
1answer
349 views
How to find out the wavelength for the blue led diode?
I need your help as I am stuck and I dont know where to start. I have got four blue leds diode that come with dark blue led lights that I really want to get the same led colours for my 3 fans, but I ...
2
votes
4answers
96 views
How are high-energy detectors able to to distinguish between $m_{e}$ and $m_{\mu}$?
I had a teacher pose this interesting question yesterday:
Suppose you're running a high-energy scattering experiment at the LHC. For concreteness, let's suppose it's a 2 to 2 scattering event which ...
6
votes
0answers
211 views
How to cleave a perovskite single-crystal in vacuum?
I am trying to cleave the lead-halide perovskite in vacuum to study its intrinsic electronic properties using photoelectron spectroscopy, since it is difficult to remove surface adsorption without ...
1
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1answer
98 views
Phase-shifting by Acousto-Optic modulators
I am working on a project where I need to be able to introduce a phase-shift to a light pulse, without any mechanical parts involved. One of the options is to use an acousto-optic modulator:
...
